@Manual{ user_tutorial,
	author = "{Alessandro Cimatti Emanuele Olivetti Gavin Keighren Marco Pistore and Marco Roveri} {Roberto Cavada}",
	title = "NuSMV 2.2 User Manual",
	publisher = "Addison-Wesley",
	year = 2005
}

@Manual{ tutorial,
	title = "NuSMV 2.2 Tutorial",
	author = "{Alessandro Cimatti Emanuele Olivetti Gavin Keighren Marco Pistore and Marco Roveri} {Roberto Cavada}",
	year = "2005"
}

